[C++-sig] incorrect linking to libpython
Dane Springmeyer
blake at hailmail.net
Sat Feb 27 03:36:16 CET 2010
Amos,
I feel your pain, seriously. I've been down many of these paths as well.
My overall sense is that direct linking of boost to a python
executable may not be necessary, and rather that bjam could use `-
undefined dynamic_lookup`, which will mean that when you import the
python module you've built with boost::python the right version of
python will be dynamically looked up based on the interpreter you are
running. There are certainly potential problems with this route (and
I've only lightly tested so far) but I think it may hold promise.
More to the point, I've also got into the habit of passing -Z to the
linker to make sure that if the custom python framework is not able to
be linked, ld does not fallback to linking to the "system" or apple
provided python framework and rather throws an error so you know the
exact point things went wrong rather than only later by getting the
dreaded "Version Mismatch" error.
Failing to link to the /Library or user installed python26 is almost
invariably the case on snow leopard because two copies will exist and
the user installed version won't be preferentially linked with the
normal -L/path/to/dir -lpython2.6 method because 'libpython2.6' is
actually:
/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/config/
libpython2.6.a
and my sense is the linker will prefer the /usr/lib/libpython2.6.dylib
over that because of the 'a' (even though it is actually, and oddly, a
symlink to the dynamic library at:
/Library/Frameworks/Python.framework/Versions/2.6/Python
So, one workaround is symlinking:
/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/config/
libpython2.6.dylib -> ../../../Python
Then bjam should be able to find it.
But I think a preferable method would be if bjam actually sent the
linker line:
-F/Library/Library/Frameworks -framework Python -Z
instead of -L/etc/etc -lpython...
Dane
More info on those ld commands at:
http://developer.apple.com/mac/library/DOCUMENTATION/Darwin/Reference/ManPages/man1/ld.1.html
On Feb 26, 2010, at 3:47 PM, Amos Anderson wrote:
> Hello --
>
> summary: I'm trying to compile the boost python library using a custom
> installed python on osx. however, it appears to be linking to the
> system library, not the installed library.
>
>
> I'm using OSX 10.6.2, which has python 2.6.1 by default. I wanted to
> try to install 2.6.4 just to see how the process works. I
> To install python, I did this:
> ./configure --enable-framework
> make
> make install
>
> which put the distribution here:
> /Library/Frameworks/Python.framework/Versions/2.6/bin/python2.6
>
> I changed a boost config file to read:
> using python
> : 2.6
> : /Library/Frameworks/Python.framework/Versions/2.6/bin/python2.6
> : /Library/Frameworks/Python.framework/Versions/2.6/include/
> python2.6
> : /Library/Frameworks/Python.framework/Versions/2.6/lib/
> python2.6/config ;
>
> and compiled the library. However, when I examine the library itself:
> % otool -L libboost_python.dylib
> libboost_python.dylib:
> libboost_python.dylib (compatibility version 0.0.0, current version
> 0.0.0)
> /System/Library/Frameworks/Python.framework/Versions/2.6/Python
> (compatibility version 2.6.0, current version 2.6.1)
> /usr/lib/libstdc++.6.dylib (compatibility version 7.0.0, current
> version 7.9.0)
> /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current
> version 125.0.0)
>
> I can see that it linked to the system's version. Why did it choose
> that one? The problem is that when I run my code, I get the error:
> Fatal Python error: Interpreter not initialized (version mismatch?)
> ../../../triad.sh: line 9: 59136 Abort trap python $@
>
>
> the OS gives me a popup window mentioning all the linked libraries:
> Binary Images:
> 0x100000000 - 0x100000ff7 +org.python.python 2.6.4
> (2.6.4) <536A2002-9AEC-D7DF-8C2B-6C634FB7F37E>
> /Library/Frameworks/Python.framework/Versions/2.6/Resources/
> Python.app/Contents/MacOS/Python
> 0x100003000 - 0x100153fe7 +org.python.python 2.6.4, (c)
> 2004-2008 Python Software Foundation. (2.6.4)
> <3B4D8CE1-8D9C-97CB-57BA-A8F4C40CE5F0>
> /Library/Frameworks/Python.framework/Versions/2.6/Python
> 0x1002e7000 - 0x1002e8ff7 +time.so ??? (???)
> <CB23D26C-1417-4D31-9E06-1E33CCDCA83C>
> /Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/lib-
> dynload/time.so
> 0x100480000 - 0x100493fef +libgcc_s.1.dylib ??? (???)
> <E51F2952-8BEB-C427-10A9-672FC10E3A54> /usr/local/lib/libgcc_s.1.dylib
> 0x100753000 - 0x10077bfff +libboost_wserialization.dylib
> ??? (???) <4FD94C16-75D0-DE5D-A27B-E3AEAEEA8CCC>
> /Users/amos/triad/trunk/lib/libboost_wserialization.dylib
> 0x101000000 - 0x1013eeff7 +triad.so ??? (???)
> <EEF65664-60F0-E721-06A8-82F88CEA1EFC>
> /Users/amos/triad/trunk/lib/triad.so
> 0x1020eb000 - 0x102124fef +libboost_serialization.dylib
> ??? (???) <33DB6DD1-4712-AEE1-0761-18054566A5E4>
> /Users/amos/triad/trunk/lib/libboost_serialization.dylib
> 0x1021b1000 - 0x1021f0ff7 +libboost_python.dylib ???
> (???) <67258016-C11E-8EDF-BF36-103DBC219C78>
> /Users/amos/triad/trunk/lib/libboost_python.dylib
> 0x10223e000 - 0x10234eff7 org.python.python 2.6.1
> (2.6.1) <01EBD0D4-F181-045F-C7A8-B7B3C5D4204F>
> /System/Library/Frameworks/Python.framework/Versions/2.6/Python
> 0x7fff5fc00000 - 0x7fff5fc3bdef dyld 132.1 (???)
> <B633F790-4DDB-53CD-7ACF-2A3682BCEA9F> /usr/lib/dyld
> 0x7fff813dc000 - 0x7fff81459fef libstdc++.6.dylib ??? (???)
> <35ECA411-2C08-FD7D-11B1-1B7A04921A5C> /usr/lib/libstdc++.6.dylib
> 0x7fff81f2c000 - 0x7fff81f3dfef libz.1.dylib ??? (???)
> <3A7A4C48-A4C8-A78A-8B87-C0DDF6601AC8> /usr/lib/libz.1.dylib
> 0x7fff846e0000 - 0x7fff846e4ff7 libmathCommon.A.dylib ???
> (???) <95718673-FEEE-B6ED-B127-BCDBDB60D4E5>
> /usr/lib/system/libmathCommon.A.dylib
> 0x7fff888bb000 - 0x7fff88a79ff7 libSystem.B.dylib ??? (???)
> <526DD3E5-2A8B-4512-ED97-01B832369959> /usr/lib/libSystem.B.dylib
> 0x7fffffe00000 - 0x7fffffe01fff libSystem.B.dylib ??? (???)
> <526DD3E5-2A8B-4512-ED97-01B832369959> /usr/lib/libSystem.B.dylib
>
> Where i've deleted all the lines with my libraries. Note: I can do
> this:
> /Library/Frameworks> sudo mv Python.Framework temp.Python.Framework
> and then everything works fine. So I assume that the problem is the
> one python file 2.6.1 which didn't come from the same python path as
> the other python paths. When I compile, I get this:
> % bjam -d 2 release
> ...
> deleted similar lines
> ....
> "g++" -ftemplate-depth-128 -O3 -finline-functions -Wno-inline
> -Wall -dynamic -no-cpp-precomp -gdwarf-2 -fPIC -DBOOST_ALL_NO_LIB=1
> -DBOOST_PYTHON_SOURCE -DNDEBUG
> -I"/Library/Frameworks/Python.framework/Versions/2.6/include/
> python2.6"
> -I"boost/boost_1_40_0" -c -o
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> import.o"
> "boost/boost_1_40_0/libs/python/src/import.cpp"
>
> darwin.compile.c++
> boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> exec.o
>
> "g++" -ftemplate-depth-128 -O3 -finline-functions -Wno-inline
> -Wall -dynamic -no-cpp-precomp -gdwarf-2 -fPIC -DBOOST_ALL_NO_LIB=1
> -DBOOST_PYTHON_SOURCE -DNDEBUG
> -I"/Library/Frameworks/Python.framework/Versions/2.6/include/
> python2.6"
> -I"boost/boost_1_40_0" -c -o
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> exec.o"
> "boost/boost_1_40_0/libs/python/src/exec.cpp"
>
> darwin.compile.c++
> boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> object/function_doc_signature.o
>
> "g++" -ftemplate-depth-128 -O3 -finline-functions -Wno-inline
> -Wall -dynamic -no-cpp-precomp -gdwarf-2 -fPIC -DBOOST_ALL_NO_LIB=1
> -DBOOST_PYTHON_SOURCE -DNDEBUG
> -I"/Library/Frameworks/Python.framework/Versions/2.6/include/
> python2.6"
> -I"boost/boost_1_40_0" -c -o
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> object/function_doc_signature.o"
> "boost/boost_1_40_0/libs/python/src/object/function_doc_signature.cpp"
>
> darwin.link.dll
> boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> libboost_python.dylib
>
> "g++" -dynamiclib -Wl,-single_module -install_name
> "libboost_python.dylib"
> -L"/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/
> config"
> -o "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> libboost_python.dylib"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> numeric.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> list.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> long.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> dict.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> tuple.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> str.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> slice.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> converter/from_python.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> converter/registry.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> converter/type_id.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> object/enum.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> object/class.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> object/function.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> object/inheritance.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> object/life_support.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> object/pickle_support.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> errors.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> module.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> converter/builtin_converters.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> converter/arg_to_python_base.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> object/iterator.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> object/stl_iterator.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> object_protocol.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> object_operators.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> wrapper.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> import.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> exec.o"
> "boost/boost_1_40_0/bin.v2/libs/python/build/darwin-4.2.1/release/
> object/function_doc_signature.o"
> -lpython2.6 -headerpad_max_install_names -Wl,-dead_strip
> -no_dead_strip_inits_and_terms
>
> So again we can see that it's finding the header files for each object
> file, but then when they're all being linked, it's seems to be
> skipping the library that (I think) it should be picking:
> /Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/
> config> ls -lrt
> total 208
> -rw-r--r-- 1 root admin 3.7K Feb 26 12:25 python.o
> -rwxr-xr-x@ 1 root admin 7.3K Feb 26 12:25 makesetup*
> -rwxr-xr-x@ 1 root admin 7.0K Feb 26 12:25 install-sh*
> -rw-r--r--@ 1 root admin 1.4K Feb 26 12:25 config.c.in
> -rw-r--r-- 1 root admin 2.0K Feb 26 12:25 config.c
> -rw-r--r-- 1 root admin 41B Feb 26 12:25 Setup.local
> -rw-r--r-- 1 root admin 368B Feb 26 12:25 Setup.config
> -rw-r--r--@ 1 root admin 18K Feb 26 12:25 Setup
> -rw-r--r-- 1 root admin 42K Feb 26 12:25 Makefile
> lrwxr-xr-x 1 root admin 15B Feb 26 12:25 libpython2.6.a@ -
> > ../../../Python
>
>
> I tried changing the name of the library to something else more unique
> and manually ran the link line (outside of bjam), and I *can* link to
> it, so that's not the problem. Why isn't it choosing the -L selected
> libpython2.6.a? Or maybe I'm doing something else wrong. Or maybe it's
> Apple's fault, or maybe I need to update boost from 1.40.
>
>
> amos.
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